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Vaporization (or vapo(u)risation) of an element or compound is a phase transition from the liquid phase to vapor. [1] There are two types of vaporization: evaporation and boiling . Evaporation is a surface phenomenon , whereas boiling is a bulk phenomenon (a phenomenon in which the whole object or substance is involved in the process).
Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. [1] A high concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidity affects rate of evaporation of water. [ 2 ]
Water vapor can also be indirect evidence supporting the presence of extraterrestrial liquid water in the case of some planetary mass objects. Water vapor, which reacts to temperature changes, is referred to as a 'feedback', because it amplifies the effect of forces that initially cause the warming. Therefore, it is a greenhouse gas. [2]
Temperature-dependency of the heats of vaporization for water, methanol, benzene, and acetone. In thermodynamics, the enthalpy of vaporization (symbol ∆H vap), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy that must be added to a liquid substance to transform a quantity of that substance into a gas.
of vaporization, Δ vap H o: 44.0 kJ/mol ... Vapor-liquid equilibrium for isopropanol/methanol [4] P = 101.325 kPa BP temp. °C % by mole methanol liquid vapor
This is illustrated in the vapor pressure chart (see right) that shows graphs of the vapor pressures versus temperatures for a variety of liquids. [7] At the normal boiling point of a liquid, the vapor pressure is equal to the standard atmospheric pressure defined as 1 atmosphere, [ 1 ] 760 Torr, 101.325 kPa, or 14.69595 psi.
This boiling point elevation is a challenge for vapor-compression evaporation in that it increases the pressure ratio that the steam compressor must attain to effect vaporization. Since boiling point elevation determines the pressure ratio in the compressor, it is the main overall factor in operating costs.
An ampule of nitrogen oxide vapor: brown nitrogen dioxide and colorless dinitrogen tetroxide, in equilibrium. In physics, a vapor (American English) or vapour (Commonwealth English; see spelling differences) is a substance in the gas phase at a temperature lower than its critical temperature, [1] which means that the vapor can be condensed to a liquid by increasing the pressure on it without ...